In this paper we consider a few important questions concerning the microuniverse of elementary physical systems. We know leptonic matter is characterized by negative electric charge and leptonic antimatter by positive electric charge. Conversely baryonic matter is characterized by positive electric charge and baryonic antimatter by negative electric charge. In the Non-Standard Model both, matter and antimatter, can have negative values of mass (antimass) for greater speeds than the critical speed. We will demonstrate, always in the order of the Non-Standard Model, there is a full symmetry for elementary particles in regard to the behavior of matter, antimatter and antimass whether when they are in the leptonic state or in the baryonic state. The physical reality of nature shows neverheless in the Elementary Universe a Principle of Asymmetry is in force. In fact if this Principle doesn't exist then in the Universe and in Nature we would have to observe a comparable quantity of matter and antimatter. It is known instead that the practically exclusive presence of matter, above all at low energy, is proved. Our object now is to discover that principle of Asymmetry, that in our physico-mathematical model represents a surmounting of the concept of spontaneous breaking of the symmetry, that is assumed in the Standard Model. We will demonstrate the Principle of Asymmetry is based upon a criterion of stability that identifies the actual asymmetry of the Elementary Universe with the instability state of some microphysical structures. This paper represents the second essay of the "Trilogy on the knowable Universe".